Pressure signs way below max load

[Mc Fraser]

Ladies and Gents,
I have a Win M70 in 300 win mag that has a 29in Krieger barrel with a brake and glass bedding done by a reputable gunsmith.
I understand how min and max loads from reloading books work, however beyond that could you think at any other reason why I see pressure signs below max load. I use Norma brass new and fire formed and I constantly see pressure signs 1.5 to 2.5 grain below max load with with different powders and bullets. H1000 imr 7828ssc, retumbo

 

[FEENIX]

Make sure your powder measure scale is calibrated/accurate for starters.

 

[Remmy700]

Feenix made a great point. Beyond that every rifle is different so that min and max is more of a place to give u a good idea of the realm u need to be. Also seating depth comes into play and correlates very closely to an additional item to pay close attention. Example being bullets jammed into the lands, bullets seated deep which all factor into making another element to up pressure. Could just be your rifle brother. Also brass thickness, thicker brass vs thinner brass all correlate to case capacity which directly tie into pressure. What bullet u running and what kinda powder charges are u seeing pressure brother?

 

[Mc Fraser]

Thank you.
I forgot to mention that I am very conscious about my loads, I use the RCBS Chargemaster Lite in conjunction with the RCBS beam and myweigh 300 II for every load. judging by the amount of research done and how anal I am with my scales I doubt powder weight inaccuracy is the issue. A fellow shooter has an autotrycler i should check my scales against his who knows maybe all 3 are broke or even something within my environment that i missed ...
I thought that maybe there is something with the chamber or the rifle itself that cause this behaviour ...

 

[Joefrazell]

What kinda speed are you getting? It's possible your chamber and barrel are just pressured out.

 

[Mc Fraser]

Feenix made a great point. Beyond that every rifle is different so that min and max is more of a place to give u a good idea of the realm u need to be. Also seating depth comes into play and correlates very closely to an additional item to pay close attention. Example being bullets jammed into the lands, bullets seated deep which all factor into making another element to up pressure. Could just be your rifle brother. Also brass thickness, thicker brass vs thinner brass all correlate to case capacity which directly tie into pressure. What bullet u running and what kinda powder charges are u seeing pressure brother?

Berger 215 VLD Hunting, 200 and 212 eldx book seating depth, way below measured OAL which I measured with the hornady tool and with the sharpie bullet method. I cant remember from the top of my head the loads but they are from the Hornady and Berger book.

 

[Mc Fraser]

Average 3100 fps +- 75 fps measured with labradar

 

[Remmy700]

Just going out on a limb but that seating depth could be contributing a little. Book seating depths are always super safe which is good but one of the main benefits to reloading your own pills is seating that bullet closer to the lands while also giving u some more case capacity. Is there a reason u seating so deep?

 

[Remmy700]

Average 3100 fps +- 75 fps measured with labradar

Wow! That is moving for a 215 out of a 300 win. What is the +or - 75 FPS? That isn't your ES is it?

 

[Mc Fraser]

What kinda speed are you getting? It's possible your chamber and barrel are just pressured out.

Just going out on a limb but that seating depth could be contributing a little. Book seating depths are always super safe which is good but one of the main benefits to reloading your own pills is seating that bullet closer to the lands while also giving u some more case capacity. Is there a reason u seating so deep?

I want to find the velocity node first, therefore I start with the seating depth from the book. Eventually, I will move the bullet closer to the lands but I'm not there yet.

 

[Remmy700]

I load 300 win a lot and it u running 215s at that speed u running some powder and I would guess over max. Unless u just have a really, really fast barrel.

 

[FEENIX]

Berger 215 VLD Hunting, 200 and 212 eldx book seating depth, way below measured OAL which I measured with the hornady tool and with the sharpie bullet method. I cant remember from the top of my head the loads but they are from the Hornady and Berger book.

Slow down a bit, you're kind of all over the place. Let's try to troubleshoot one problem at a time. "If" you cannot remember your load configuration, I suggest create a log book of your load with all the pertinent information. You listed 3 different bullet weights and powders but no load configuration.

 

[Mc Fraser]

This is an example of a test that I have handy, 200gr Sierra Gameking SBT, Sierra reloading book says 77.5gr max charge, I had pressure signs at 76gr, at 78gr the primer was in place but with small holes through it, I could see the light. This was also the first and last time when I pushed the envelope that far. Barrel twist is 1:10 5R

 

[Remmy700]

If u had pressure at 76 why would u even try 78?